It has previously been proposed--see for example German Pat. No. 21 36 227--to fold papers and then, in order to permit the addition of inserts, to open the folded paper products by means of a separating element. A typical application is the introduction of inserts into already folded paper materials, such as newspapers. In accordance with various structures, of which the German Pat. No. 21 36 227 is representative, a separate apparatus is needed in order to re-open the folded paper products. This increases the cost of the overall apparatus and, hence, increases the cost of handling of the paper products and renders the entire system more complex.
Various types of folding apparatus are known and customary in the printing and paper handling field. German Pat. No. 31 42 242 describes a system in which a folding flap cylinder is used which cooperates with a folding blade cylinder which, simultaneously, also may be a collection cylinder. The fold is formed in this way: A sheet, or a group of superimposed sheets, or a package of sheets, is placed on the folding blade cylinder and the folding blade, which is controllably located on the folding blade cylinder, pushes the sheet or package of sheets at an intermediate position in an opened folding flap of the folding flap cylinder. A rotating transport device, for example a bucket wheel, then removes the now folded paper products from the folding apparatus.
Another type of folding apparatus is known, referred to as a drum folding apparatus. Rather than using a folding flap cylinder and a folding blade cylinder, a pair of folding rollers are used, between which a folding blade can be inserted in order to push sheets or a package of sheets between the folding rollers which, then, continue to grip the folded sheet or package of sheets and transport the now folded sheet or package of sheets in the nip between the two folding rollers or drums.